4. Characteristics of studies ‐ test details.
|
Author, year of publication [year of study] |
Reference test used (PTr/INR) | Any other measures taken (e.g. PT, APTT, fibrinogen level, platelet count, fibrinogen degradation products) | Index test used (TEG/ROTEM) and version of device | Measure used and threshold | Origin of threshold | Other available index test measures | % disease prevalence (PTr > specified range) |
|
Davenport, 2011 [2007‐2009] |
Laboratory PT ratio of > 1.2 | Platelet and fibrinogen measured but not used to define reference standard. Need for massive transfusion also considered as marker of coagulopathy and sensitivity of TEG to predict massive transfusion calculated | ROTEM delta (Pentapharm GmbH, Munich, Germany). STARTEM (recalcitrant) and EXTEM (tissue factor derived from rabbit brain) protocols employed | EXTEM CA5 (clot amplitude at 5 minutes) ≤ 35 mm | Based on maximum separation between normal and acute traumatic coagulopathy patients in study. Also noted to be 1 SD below normal range | Clotting time (s); clot formation time (s); alpha angle (degrees); maximum clot firmness (mm) | 8% |
|
Rugeri, 2007 [2004] |
PT ratio of > 1.5 of control PT. MDA II instrument used to measure all coagulation measures | APTT > 1.5 of control; fibrinogen < 1 g/L (Fibriquick/Clauss technique); platelets < 50 x109/L (SE‐9500) ‐ all used as alternative definitions of coagulopathy | ROTEM (model not specified). INTEM, EXTEM and FIBTEM screening tests | EXTEM CA15 (clot amplitude at 15 minutes) = 32 mm | Unclear, but appears to be based on results of correlation between ROTEM results and standard measures of coagulation | Clotting time (s); clot formation time (s); alpha angle (degrees); maximum clot firmness (mm); CA10 and CA15 | 28% |
|
Woolley, 2012 [2009] |
"Standard lab testing in the hospital lab". PT > 1.5 times normal (corresponding to PT > 18 s) | Main focus of evaluation was examining accuracy relative to ROTEM EXTEM MCF < 40 mm | ROTEM (TEM International GmBH, Munich, Germany). STARTEM (calcium), EXTEM (tissue factor) and FIBTEM (platelet inhibitor, cytochalasin D) screening tests | EXTEM CA5 and CA10 below reference range. For Camp Bastion CA5 32‐71 mm CA10 40‐72 mm (derived from 50 uninjured volunteers). Manufacturer CA10 43‐65 mm | Reference range. For Camp Bastion results based on 50 uninjured volunteers ‐ members of the Emergency Blood Donor Panel | Clotting time (s); clot formation time (s); alpha angle (degrees); maximum clot firmness (mm) | 51% |
Abbreviations
APTT: activated partial thromboplastin time CA5: clot amplitude at 5 minutes CA10: clot amplitude at 10 minutes CA15: clot amplitude at 15 minutes EXTEM: tissue factor activated citrated and recalcified blood sample FIBTEM: tissue factor plus platelet inhibitor cytochalasin D activated citrated and recalcified blood samples INR: International Normalized Ratio PT: prothrombin time PTr: pro‐thrombin time ratio ROTEM: rotational thromboelastometry SD: standard deviation STARTEM: a liquid system reagent for recalcifying citrated blood or plasma TEG: thromboelastography